USB port not working??????

I have a MacBook Pro 13" 2.3GHz with Mac OS X Lion. Recently I have encountered very strange problems with my MacBook. Firstly, my macbook suddenly started booting slowly. When I opened it today, I found that it was booting up slowly. It was not opening the applications that it opens on the start. Secondly, one of my usb ports is not reading the device I connect it to. I connected my Seagate Expansion Drive to it and the light on my hard disk lit up like it does normally. But it is not showing up in my MacBook. But when I connected to the other drive it worked perfectly. I thought of it as a hardware problem, but why would the light on my hard disk light up if that was the case??? Please provide me a solution to this problem. Thank you.

Hi. Have you done a recent software upgrade or something? It's probably a matter of broken kexts (i'm not sure), but can be fixed. I'd suggest you to consult your nearest Apple store, that's the best option in such a case.